Open-end rotor spinning machine

ABSTRACT

An open-end rotor spinning machine having a plurality of work stations, wherein each work station comprises an open-end spinning device for manufacturing a yarn, a winding device with a creel, a yarn traversing device for producing a cheese, a pivotably supported, vacuum-chargeable suction nozzle, an individual drive for pivoting the suction nozzle between a yarn take-up position in the area of the winding device and a yarn transfer position in the area of a spinning piecing member, and a device for preparing a yarn end required for restarting spinning. Each work station comprises a winding device with a drive drum driven by a reversible individual drive for driving a cheese and with a yarn traversing device driven by an individual motor for defined placement of the yarn running up onto the cheese, a yarn withdrawal device, and a work-station computer for controlling the individual drives and individual motors.

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims the benefit of German Patent Application DE 10139075.0, filed Aug. 9, 2001, herein incorporated by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to an open-end rotor spinning machine having at least two similar work stations, in particular to an open-end rotor spinning machine having numerous individual drives at the individual work stations wherein the individual drives can be controlled in a defined manner by a work-station computer.

BACKGROUND OF THE INVENTION

[0003] As illustrated in German Patent Publication DE 198 36 065 A1, an open-end rotor spinning machine typically has a plurality of similar work stations arranged in series adjacent to each other. A sliver placed, for example, in a spinning can is spun into a yarn in these work stations and subsequently wound into a cheese.

[0004] Each work station has an open-end spinning device and a winding device. The working parts of the spinning device and also the working parts of the winding device are driven by drive means running the length of the machine. For example, a tangential belt for driving the spinning rotors and a full-length drive shaft driven on the machine end for driving the sliver draw-in cylinder are arranged in the area of the spinning devices.

[0005] A corresponding, full-length drive shaft on which the so-called drive drums for the cheeses are fixed runs in the area of the winding device. Moreover, these work stations comprise yarn withdrawal devices driven by a full-length drive shaft.

[0006] The work stations are serviced by a service unit that patrols the work stations of the rotor spinning machine and engages automatically when a problem such as a yarn break occurs at one of the work stations. In such an instance, the service unit runs to the work station concerned, locks thereat and searches for the broken yarn run up after the yarn break onto the cheese with a pivotably supported, vacuum-chargeable suction nozzle.

[0007] In some situations, the individual work stations may have to wait too long for the service unit. This is the case when, for example, the service unit is still occupied with eliminating a yarn break at another work station. To avoid this delay, it has been proposed to employ several of the service units simultaneously at an open-end spinning machine.

[0008] However, service units such as those disclosed in German Patent Publication DE 198 27 605 A1 are on the whole relatively complicated in design, and therefore, rather expensive. In addition to a vacuum-chargeable suction nozzle, the service units also have a number of manipulating elements that make it possible for the service unit to search for the yarn that has run up on the cheese after a yarn break and to restart the spinning of the taken-up yarn after appropriate preparation in the open-end spinning device of the particular work station on a yarn ring rotating there. The drive of the individual yarn manipulating elements, including the suction nozzle, takes place via special lever linkages that correspond with a cam disk packet. The cam disk packet is driven by a main motor.

[0009] German Patent Publication DE 25 41 589 A1 teaches a comparable, moveable service unit also designed for automatically restarting the spinning of the previously disclosed work stations of an open-end rotor spinning machine. This known service unit has a pivotably supported, slotted suction nozzle that merges into a slotted transfer arm. In addition, a yarn grasper is installed in the area of the pivot axis of the suction nozzle which grasper transfers the yarn taken up by the suction nozzle to a yarn clamping and preparing device arranged on the end of the transfer arm. Even though German Patent Publication DE 25 41 589 A1 does not expressly disclose by what type of drive mechanism, for example, the suction nozzle, yarn grasper and yarn storage can be driven, it can be assumed that the drive of these yarn manipulating devices takes place, as is customary and shown, for example in German Patent Publication DE 198 27 605 A1, via a cam disk packet driven by a main motor.

[0010] The previously cited German patent publication does mention that the yarn manipulating devices of the service unit could theoretically also be arranged at each one of the work stations of the spinning machines. However, a 1:1 transfer is expressly advised against.

[0011] According to German Patent Publication DE 25 41 589 A1, it is supposedly more economical to arrange the expensive yarn manipulating devices on a moveable service unit that then services a plurality of work stations of an open-end spinning machine.

SUMMARY OF THE INVENTION

[0012] It is accordingly an object of the present invention to create an open-end spinning machine with work stations that are as self-sufficient as possible but yet relatively simple in design.

[0013] According to the present invention, this object is addressed by an open-end rotor spinning machine having at least two work stations, wherein each work station comprises an open-end spinning device for manufacturing a yarn, a winding device with a creel, a yarn traversing device for producing a cheese, a pivotably supported, vacuum-chargeable suction nozzle wherein the suction nozzle can pivot via an individual drive between a yarn take-up position in the area of the winding device and a yarn transfer position in the area of a spinning piecing member, and a device for preparing a yarn end required for restarting spinning. Each work station of the open-end rotor spinning machine comprises a winding device with a drive drum driven by a reversible individual drive for driving a cheese and with a yarn traversing device driven by an individual motor for defined placement of the yarn running up onto the cheese. Each work station also comprises a yarn withdrawal device driven by an individual motor wherein the individual drives can be controlled in a defined manner by a work-station computer.

[0014] In one embodiment of the present invention, the work stations of an open-end rotor spinning machine are designated with numerous individual drives at the individual work stations wherein the individual drives can be controlled in a defined manner by a work-station computer. This embodiment has the particular advantage that such work stations can increase the productivity of the open-end spinning machine. The individual drives for the drive drums and/or the yarn withdrawal device are preferably designed, for example, as synchronous motors.

[0015] The design of the work stations makes possible an immediate and rapid elimination of any occurring yarn breaks, so that the downtime of the work stations caused by yarn breaks can be minimized and have a lesser impact on the efficiency of the open-end spinning machine.

[0016] For this reason, it is also possible to efficiently produce less spin-resistant yarn in work stations in accordance with the present invention. In accordance with the present invention, it is possible to produce a yarn that has a distinctly lower twist factor as compared to yarn produced by known work stations. Although the yarn produced in accordance with the present invention is more sensitive to yarn breaks, the result is a distinct increase of the yarn length produced at the same rotor speed of the spinning device.

[0017] In another embodiment of the present invention, a stepping motor is provided as the individual drive for the suction nozzle forming part of the work station. The stepping motor is connected via a control lead to the work-station computer and can be controlled in a defined manner via the work-station computer. The suction nozzle that is driven by a stepping motor can be adjusted between a yarn take-up position in which the mouth opening of the suction nozzle is positioned in the immediate vicinity of the jacket surface of a cheese, that is held in the creel of a winding device and driven in the direction of unwinding, and between a yarn transfer position in which the taken-up yarn is presented to a spinning piecing member in the area of the spinning device. The suction nozzle can also be multiply pivoted in succession between these two end positions as required so that even in the case of difficult yarns a high degree of safety as regards a successful yarn transfer is given.

[0018] Such stepping motors have the particular advantage that on the one hand they can be positioned precisely without great control cost and in a reproducible manner at all times and on the other hand are relatively economical commercially as readily obtainable serial components.

[0019] In yet another embodiment of the present invention, a pivotably supported centering sheet can be arranged in front of the yarn traversing device which sheet can be folded into the regular path course by a stepping motor or by a pneumatic cylinder. The centering sheet acts in cooperation with an appropriate yarn guide notch in the mouth opening of the suction nozzle such that the yarn that ran up after a yarn break onto the jacket surface of the cheese is guided in the middle of the work station while it is moved back by the suction nozzle to a spinning piecing member arranged in the area of the spinning device. The pivoted-in centering sheet assures that the yarn can glide along a stationary yarn guide device arranged in front of the regular yarn path and can be positioned in a catch element of this yarn guide device in such a manner that it can be subsequently readily taken over by a yarn catch element arranged on the suction nozzle and able to pivot with the latter.

[0020] Each work station also comprises a pneumatic yarn storage nozzle and a mechanical yarn storage device. The yarn overlengths that occur from time to time during the spinning restart process and also, for example, during the transfer of the yarn from the centering sheet to the yarn guide of the traversing device are compensated with preference by the pneumatic storage nozzle. The mechanical storage device driven by an individual motor is particularly useful when conical cheeses are to be wound. That is, if the yarn winding speed constantly fluctuates between a maximum and a minimum, given a constant yarn supply speed.

[0021] Such a mechanical yarn storage device also renders the using of a so-called “fish belly” superfluous, since the yarn overlengths occurring during the winding process on account of the yarn traversing are readily compensated by the mechanical yarn storage device.

[0022] In another advantageous embodiment, the yarn withdrawal device of each work station comprises a withdrawal cylinder preferably driven by a synchronous motor and comprises a pressure roller resting with a certain contact pressure on the withdrawal cylinder. The synchronous motor is reversible, so that a prescribed return of the prepared yarn into the open-end spinning device for a spinning restart as well as an orderly withdrawal of the newly produced yarn are assured.

[0023] Further details of the present invention can be gathered from a non-limiting exemplary embodiment presented in the following description with reference made to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 shows a perspective view of a work station of an open-end spinning machine in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0025] The work station 1 of an open-end rotor spinning machine is shown in FIG. 1. Such a work station 1 comprises, as is known and, therefore, only schematically shown, an open-end spinning device 2 and a winding device 3. Pivotably supported spinning piecing member 16 is arranged in the area of the yarn withdrawal tube 21 of open-end spinning device 2, which member 16 takes the yarn 9 fetched after a yarn break by suction nozzle 4 from cheese 8 and prepares the yarn end for the restarting of spinning.

[0026] Moreover, yarn withdrawal device 27 is arranged in this area, which takes over the withdrawal of spinning yarn 9 from the open-end spinning device during the regular spinning operation and also is responsible during the restarting of spinning for the return of prepared yarn 9 into the open-end spinning device.

[0027] Winding device 3 is comprised, as is customary, of creel 22 for rotatably holding a cheese 8, of drive drum 23, preferably driven via reversible individual drive 56, and of yarn traversing device 24 driven, for example, via stepping motor 57. In addition, a yarn centering device in the form of pivotably supported centering sheet 17 can be arranged in front of yarn traversing device 24, which, sheet can be folded as required by drive 55 in a defined manner into the regular yarn path.

[0028] In addition, work station 1 comprises, as already indicated above, suction nozzle 4 that can be adjusted by stepping motor 6 in a defined manner between a yarn take-up position located in the area of winding device 3 and between a yarn transfer position located in the area of spinning device 2.

[0029] Suction nozzle 4 carries yarn catch element 7 on its back, which element comprises, for example, an S-shaped yarn guide edge, a yarn catch element and a switching sheet. Finally, stationary yarn guide device 5 with downwardly open catch element 10 is arranged at an interval in front of the regular yarn path of work station 1. Moreover, each work station 1 comprises yarn monitor 26, paraffining device 62 and yarn storage devices 60, 61.

[0030] Yarn storage device 61 is designed as a vacuum-chargeable storage nozzle whereas storage device 60 is designed as a mechanical yarn storage device. That is, an adjustable yarn guide member is arranged between two stationary yarn guide members which adjustable yarn guide member, driven by stepping motor 58, can move relative to the yarn path.

[0031] During the spinning process, yarn 9 produced in open-end spinning device 2 is withdrawn by yarn draw-off device 27 and wound to cheese 8 on winding device 3. Cheese 8, rotatably supported between the arms of creel 22, rests with its surface on drive drum 23 driven by an individual motor and is driven by the latter by friction in the direction of winding on. At the same time, yarn 9 is placed in such a manner by yarn traversing device 24 that it runs in crossing layers onto the jacket surface of the cheese 8.

[0032] Suction nozzle 4 present at each work station 1 is preferably positioned in a parked position during this “normal” spinning process; spinning piecing member 16 is in a so-called spinning position, as is indicated in FIG. 1.

[0033] If a problem such as a yarn break occurs at one of work stations 1 of the open-end rotor spinning machine, which is preferably detected by yarn monitor 26, work-station computer 25 assures that spinning device 2 of the particular work station 1 as well as the associated winding device 3 are braked to a standstill. That is, individual drive 56 of drive drum 23 is loaded with a braking current in such a manner that the drive drum is rapidly braked to a standstill. The drive drum also delays cheese 8 at this time. At the same time, stepping motor 6 of suction nozzle 4 is controlled in such a manner that suction nozzle 4 is pivoted out of its park position into a yarn take-up position (not shown) in which suction intake 19 of suction nozzle 4 is positioned in the immediate vicinity of the jacket surface of cheese 8. In addition, work-station computer 25 assures that a valve is opened and suction nozzle 4 is pneumatically and continually connected to a vacuum source (not shown).

[0034] Drive drum 23 is subsequently loaded in the direction of unwinding so that the yarn end that ran up after the yarn break onto the jacket surface of cheese 8 can be taken up by suction nozzle 4. The successful taking up of yarn 9 can be monitored by a sensor device arranged inside suction nozzle 4.

[0035] Suction nozzle 4 is then pivoted downward by stepping motor 6. While suction nozzle 4 is pivoting downward, e.g., centering sheet 17 installed in the area of winding device 3 is folded by drive 55 into the yarn path so that yarn 9 is guided by yarn guide notch 18 in centering sheet 17 and, for example, yarn guide notch 20 in suction intake opening 19 of suction nozzle 4 approximately in the middle of the work station.

[0036] While suction nozzle 4 is pivoting downward, the yarn strand stretched between yarn guide notch 18 of centering sheet 17 and between yarn guide notch 20 of suction nozzle 4 glides along stationary yarn guide device until yarn 9 finally slides into downwardly open yarn catch element 10 of yarn guide device 5. Suction nozzle 4 is subsequently pivoted somewhat upward again at first. A second yarn strand forms at this time between suction nozzle 4 and catch element 10 of stationary yarn guide device 5. Suction nozzle 4, which subsequently pivots back down again crosses the first yarn strand with the yarn contour of its yarn catch element 7 and as a result transfers yarn 9 into the area of spinning piecing member 16. Moreover, during the downward pivoting of suction nozzle 4, yarn 9 is threaded into the yarn guide elements and yarn operational elements of work station 1. That is, yarn 9 is brought, among other things, under clamping cylinder 64 of yarn withdrawal device 27, which is then closed.

[0037] Shortly before it reaches the yarn transfer position, suction nozzle 4 runs with a switching sheet against a stop of pivotably supported spinning piecing member 16 and presses the latter out of the spinning position indicated in FIG. 1 into a yarn take-up position (not shown).

[0038] Subsequently or at the same time, an electromagnetic valve is controlled by work-station computer 26 in such a manner that a suction pull is produced at the yarn exit opening of spinning piecing member 16 which pull acts on yarn 9 presented by suction nozzle 4. Yarn 9 is then separated by a yarn cutting device that is a component of spinning piecing member 16. The yarn end of yarn 9, which end is connected to cheese 9, is drawn in by suction through the yarn exit opening into spinning piecing member 16 while the separated, free yarn end is removed by suction nozzle 4. The yarn end of yarn 9 which end is fixed in spinning piecing member 16 is subsequently prepared and held ready for a spinning restart.

[0039] When suction nozzle 4 is subsequently moved back into its park position, spinning piecing member 16 automatically pivots back into the spinning position under the action of a spring element in the area of its pivot axis and comes to rest with a rear seal on yarn withdrawal tube 21 of open-end spinning device 2.

[0040] Spinning piecing member 16 is then under the influence of the vacuum prevailing inside open-end spinning device 2, so that the previously applied vacuum can be turned off. Drive 59 of yarn withdrawal device 27 forming part of the work station is subsequently controlled by work-station computer 25 in such a manner that a defined return of the yarn into open-end spinning device 2 takes place. That is, the prepared yarn end of yarn 9 is placed on a yarn ring rotating inside open-end spinning device 2, which ring is broken at this time.

[0041] The newly created yarn 9 is subsequently withdrawn via yarn withdrawal device 27 and wound, as initially mentioned already, on winding device 3 to a cheese 8.

[0042] It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof. 

We claim:
 1. An open-end rotor spinning machine having at least two work stations, wherein each work station comprises an open-end spinning device for manufacturing a yarn, a winding device with a creel, a yarn traversing device for producing a cheese, a pivotably supported, vacuum-chargeable suction nozzle, an individual drive for pivoting the suction nozzle between a yarn take-up position in the area of the winding device and a yarn transfer position in the area of a spinning piecing member, and a device for preparing a yarn end required for restarting spinning, wherein each work station of the open-end rotor spinning machine comprises: a winding device with a drive drum driven by a reversible individual drive for driving a cheese and with a yarn traversing device driven by an individual motor for defined placement of the yarn running up onto the cheese, a yarn withdrawal device driven by another individual motor, and a work-station computer for controlling the individual drives and individual motors in a defined manner.
 2. The open-end rotor spinning machine according to claim 1, wherein the individual drive for the suction nozzle is a stepping motor connected via a control lead to the work-station computer.
 3. The open-end rotor spinning machine according to claim 1, wherein a pivotably supported centering sheet driven by a stepping motor or a pneumatic cylinder is arranged in an area of the winding device.
 4. The open-end rotor spinning machine according to claim 1, wherein each work station comprises a mechanical yarn storage device driven by an individual motor and a pneumatically operated yarn storage nozzle.
 5. The open-end rotor spinning machine according to claim 1, wherein the yarn withdrawal device comprises a withdrawal cylinder loaded by a reversible individual drive and a clamping roller without a drive resting on the take-off cylinder.
 6. The open-end rotor spinning machine according to claim 5, wherein the reversible individual drive is a synchronous motor. 